<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <div id="app">
      <button @click="fn1">切换</button>
      <hr />
      <img :src="pic" alt="" />
    </div>
    <script src="./vue.js"></script>
    <script>
      new Vue({
        el: '#app',
        data () {
          return {
            pic: './images/boy.png'
          }
        },
        methods: {
          fn1 () {
            if (this.pic.indexOf('boy') != -1) {
              // 如果图片是boy就换成girl
              this.pic = './images/girl.png'
            } else {
              // 否则就换回boy
              this.pic = './images/boy.png'
            }
          }
        }
      })
    </script>
  </body>
</html>
